asin.c

MMI层OBJ不能完全编译

/****************************************************************************/
/*  asin   v2.54                                                            */
/*  Copyright (c) 1995-2004 Texas Instruments Incorporated                  */
/****************************************************************************/
#include <math.h>
#include <values.h>
#include <errno.h>

/****************************************************************************/
/*  ASIN() - Arcsine							    */
/*									    */
/*  Based on the algorithm from "Software Manual for the Elementary         */
/*  Functions", Cody and Waite, Prentice Hall 1980, chapter 10.             */
/*									    */
/*  Y = abs(x)								    */
/*  if Y > 0.5, g = (1 - Y) / 2, Y = - 2 * sqrt(g), i = 1		    */
/*  if Y < 0.5, g = Y * Y, i = 0					    */
/*  R = polynomial expression			 			    */
/*									    */
/*  result = Y + Y * R							    */
/*									    */
/*  if x < 0, result = -ci - result - ci 				    */
/*  if x > 0, result = ci + result + ci		  			    */
/****************************************************************************/
double asin(double x)
{
    double p, q, g, y;
    static const _DATA_ACCESS double c[2] = {0.0, 0.78539816339744830962};
    int i = 0;

    if ((y = fabs(x)) > 0.5)
    {
       /*******************************************************************/
       /* check if input is out of the domain of the function             */
       /*******************************************************************/
       if (y > 1.0) { errno = EDOM; return (0.0); }

       i = 1;	
       g = (1.0 - y) * 0.5;	
       y = -2.0 * sqrt(g);
    }
    else g = y * y;		

  /************************************************************************/
  /* determine polynomial expression                                      */
  /************************************************************************/
#if BITS<=24
    p = (ASP2 * g + ASP1) * g;
    q = (g + ASQ1) * g + ASQ0;
#elif BITS>=25 && BITS<=36
    p = ((ASP3 * g + ASP2) * g + ASP1) * g;
    q = ((g + ASQ2) * g + ASQ1) * g + ASQ0;
#elif BITS>=37 && BITS<=48
    p = (((ASP4 * g + ASP3) * g + ASP2) * g + ASP1) * g;
    q = (((g + ASQ3) * g + ASQ2) * g + ASQ1) * g + ASQ0;
#else
    p = ((((ASP5 * g + ASP4) * g + ASP3) * g + ASP2) * g + ASP1) * g;
    q = ((((g + ASQ4) * g + ASQ3) * g + ASQ2) * g + ASQ1) * g + ASQ0;
#endif

    return (x < 0) ? (-((c[i] + y + y * p / q) + c[i]))
		   : ((c[i] + y + y * p / q) + c[i]);
}